A data processing system includes a display control unit of implementing a display module for displaying at least one format file containing a fixed format, and at least one data file containing item data to be set to the fixed format, a specifying control unit of implementing a specifying module for specifying any one of the format file and the data file, and also specifying the other category of file from this one file, and a setting unit of setting the item data of the data file to the fixed format of the format file in accordance with the specifying operation. This architecture makes it possible to easily input the item data to the fixed format by manipulations on the screen.